(i) Field of the Invention
The present invention relates to an ink composition for use in an alcoholic marking pen. More specifically, it relates to an alcoholic marking pen ink composition which is excellent in fixing properties and whitening resistance of writings on the nonabsorbent surface of a glass, a metal, a resin or the like.
(ii) Description of the Related Art
In inks for oil marking pens, aromatic hydrocarbon solvents such as xylene and ketone solvents have been heretofore used which have good solubility in an oil-soluble dye, but these solvents have problems of safety to people such as odor and toxicity. For this reason, it is necessary on occasion that restrictions and limitations are put on the usage and use circumstances thereof.
In order to solve these problems, alcoholic inks mainly comprising alcohol solvents which are less odorous and less toxic, particularly ethanol inks containing ethanol as the main solvent have been developed in recent years. However, these alcoholic inks have the following drawbacks:
(1) When something is written on a nonabsorbent surface, the fixing power of the handwriting is weak. Therefore, when lightly rubbed, the handwriting is easily erased. PA1 (2) Since ethanol has hygroscopicity, the handwriting absorbs moisture immediately after the writing on the nonabsorbent surface, and a whitening phenomenon occurs. PA1 (3) The ink present at a penpoint or in an ink fountain absorbs moisture, and a water-insoluble resin component precipitates and leads to clogging and ink scratch. As a result, the writing becomes impossible. With the intention of solving this problem, an invention has been disclosed in Japanese Patent Publication No. Hei-2-53470/1990. However, the addition of solvents mentioned in this publication is not satisfactory in points of quick-drying properties and toxicity.